The invention relates to a method for monitoring a workpiece during a transportation and/or production process with at least one workpiece agent assigned to the workpiece.
From the prior art, methods are known by which a fixed association between workpiece agent and workpiece is provided. If one workpiece agent fails, the workpiece flow goes out of control, so that the workpiece must be removed from the transportation and/or production operation. A fixed association between workpiece agent and workpiece also hinders the new incorporation of unknown workpieces into the transportation and/or production process. In the prior art, that always requires defining a new workpiece agent.
The object of the present invention is to refine a method of the type defined above such that on the one hand the freedom from failure of the transportation and/or production process is increased and on the other hand the incorporation of new workpieces into the transportation and/or production process is facilitated.
This object is attained according to the invention, among other provisions, in that the failure of a workpiece agent assigned to a workpiece is detected; that the monitoring of the workpiece is taken over by a further workpiece agent, and workpiece-specific data of the taken-over workpiece are contained in the workpiece agent taking over the monitoring and/or in a database and are transmitted in the workpiece agents.
In contrast to the prior art, no fixed association is made between workpiece agent and workpiece. If one workpiece agent fails, the monitoring of the workpiece can be taken over by a further workpiece agent, without impeding the transportation and/or production process as a result. In particular, the freedom of the entire production system from failure is improved.
In a preferred method procedure, it is provided that a plurality of workpieces are monitored by one workpiece agent, and workpiece-specific data are stored in the applicable workpiece agent; that the failure of the workpiece agent is detected by a transportation agent, which independently selects a functionally ready further workpiece agent for monitoring the workpiece; and that the further workpiece agent checks whether workpiece-specific data of the workpiece to be monitored are stored in memory, and if workpiece-specific data are absent, a connection with a database and/or a data carrier is made, in order to read the workpiece-specific data stored therein.
In the normal case, the workpiece is handled by one workpiece agent during the entire transportation or production process. This workpiece agent communicates with a transportation agent, in order to establish an optimal transportation route to a desired destination. If the communication between workpiece agent and transportation agent is disrupted, for instance by failure of the workpiece agent or of the communication connection, then the transportation agent independently assumes contact with a further workpiece agent, so that the latter will take over the monitoring of the workpiece to be machined in the ensuing process.
In an especially preferred method procedure, it is provided that the workpiece agent that takes over the monitoring communicates with a database, in order to obtain workpiece-specific data that are necessary for the further machining steps of the workpiece. Alternatively, it can be provided that the workpiece-specific data are contained in a data carrier, such as a memory block or magnet code, that is assigned to the workpiece, that is, either is connected directly to the workpiece or is provided on a workpiece carrier that carries the workpiece.
Preferably, the transportation agent selects a workpiece agent by the principle of randomness.
In a method procedure of independent inventive character, a workpiece newly introduced into the transportation and/or production process is preferably grasped and recorded by a transportation agent, and that the transportation agent selects a workpiece agent that is intended to take over the monitoring of the workpiece, and that the workpiece agent takes the workpiece-specific data corresponding to the new workpiece from a database and/or receives the workpiece-specific data from a data carrier coupled to the workpiece.
By this provision, the transportation and/or production process becomes quite flexible, since arbitrary workpieces can be incorporated into the process without requiring a complicated reconfiguration of the entire system.
According to the invention, each workpiece agent is constructed such that it has a control unit, which controls a plurality of units such as a transportation agent thread, workpiece agent thread and machine agent thread; a xe2x80x9cthreadxe2x80x9d is understood as the smallest processing unit of an applications program or operating system. To enable simple reconfiguration of the process, the agents communicate with one another and initialize themselves.
The agents are preferably implemented as hardware and/or software blocks in a memory-programmable controller. For communication with other PC-based units, a DECOM interface is provided.